In the field of digital communications, transmission of speeches, pictures, audios and videos has a very broad application requirement, such as cell phone communications, audio/video conferences, broadcast television, and multimedia entertainment. In order to reduce the resource occupied during storage or transmission of audio/video signals, audio/video compression coding technologies emerge. Many different technique branches emerge during the development of the audio/video compression coding technologies, where a technique of transforming a signal from a time domain to a frequency domain and then performing coding processing, also referred to as a transform-domain coding technique, is widely applied due to desired compression characteristics.
Many methods for transforming the signal from the time domain to the frequency domain exist in the transform-domain coding technique, where the time-frequency transform such as Fourier transform (Discrete Fourier transform, DFT), Discrete Cosine Transform (Discrete Cosine Transform, DCT), Discrete sine transform (Discrete sine transform, DST) and Modified Discrete Cosine Transform (Modified Discrete Cosine Transform, MDCT) has broad applications, especially in fields such as spectrum analysis, picture coding and speech coding. The signal that has undergone the time-frequency transform may be compression coded through a quantization technology, and may also be coded by using other parameter audio coding methods, thereby achieving the objective of data compression.
However, the inventor finds that, performing DCT-IV or MDCT forward transform and inverse transform directly according to transform formulas will result in high computational complexity and storage amount, and therefore, providing a time domain-frequency domain transform method with low storage amount becomes an urgent need.